In vivo Imaging Applications

In addition, these recent studies have demonstrated the potential to make a fluorescently quenched version of an ABP that produces signal only after it has 

Although proteases were originally thought to completely degrade proteins in order to maintain homeostasis of overall proteins levels in the cell, it is now clear that proteases perform limited proteolysis of substrates at defined cleavage sites. This allows proteases to regulate structure, function and localization 

Another important class of substrate-based probes for proteases uses two or more fluorophores, that are self-quenched when in close proximity. Multiple fluorophores can be linked to graft polymers containing peptide substrate sequences. When these linkers are cleaved by the protease, free fluorescent monomer can be detected. This class of probes has been widely used to study the activity of the cysteine cathepsin family of proteases aeross many diverse disease models. 

---

While Au nanorods and other NIR-active nanoparticles have untapped potential for clinical in vivo imaging applications, the focus at present is on preclinical in vitro studies to better ascertain the biological effects of these nanomaterials. Surface chemistry becomes a critical issue, as it determines the biocompatibility, dispersion stability, and site-directed targeting of nanoparticles. For example, Au nanorods coated with cetyltrimethylammonium bromide (CTAB), a cationic surfactant used during nanorod synthesis, are internalized by KB cells via a nonspecific uptake pathway within hours of its addition to the culture medium, and transported toward the... 

The identification of a pathology-associated antigen and the isolation of a specific binder (antibody, peptide, small organic molecule) does not automatically yield a novel imaging agent. Indeed, a number of conditions must be fulfilled in order to obtain a successful imaging result. In part, these conditions depend on the experimental modality chosen for the in vivo imaging application. 

Bioluminescence imaging of luciferase reporter genes is much more sensitive for in vivo imaging applications due to the lack of background bioluminescence signal [38]. Luciferases are photoenzymes isolated from a wide variety of insects. 

CMUT devices are used in the real-time in vivo imaging applications with an improved performance over the existing medical ultrasound transducers. A wafer-bonded CMUT probe showed a bandwidth of 130 %... 

The ultimate fate of a dendrimer construct in an in vivo setting is of utmost importance from both an efficacy and a toxicological point of view regardless of biological application. Different applications may have different requirements with respect to in vivo distribution and clearance time for example, dendrimers for in vivo imaging applications may be administered only once or twice in a clinical setting, whereas a dendrimer intended as dmg-delivery therapeutic may be administered multiple times over the course of the treatment. 

By using dyes that emit light in the near infrared (NIR) region of the spectrum, it is possible to generate probes that can be used for non-invasive in vivo imaging applications (see Section 2.2.3). 

Table 1 Overview of single and multi beam confocal microscope features for in-vivo imaging applications...

---